step 5—To a solution of (2,6-dimethyl-phenyl)-(hexahydro-pyrrolo[3,4-c]pyrrol-2-yl)-methanone (66, 0.12 g, 0.52 mmol) in DCM (7 mL) and THF (7 mL) was added cyclopentanecarboxylic acid (3-oxo-1-phenyl-butyl)-amide (85d, 0.15 g, 0.57 mmol). Titanium tetraisopropoxide (0.34 mL, 1.15 mmol) was added to the mixture. After 30 min NaBH(OAc)3 (0.16 g, 0.78 mmol) was added and the mixture stirred at RT for 4 h. Saturated NaHCO3 was added to the mixture and it was stirred for 10 min. The mixture was extracted with DCM and the organic layer was dried (MgSO4), filtered and evaporated. The crude product was purified by SiO2 chromatography on silica gel eluting with DCM:MeOH:NH4OH (150:10:1) to afford I-75: ms (ES+) m/z 488 (M+H); Anal. (C31H41N3O2.0.3M H2O)C; calcd, 75.51; found 75.53; H; calcd, 8.50; found, 8.29; N; calcd, 8.52; found, 8.53.
